The model we offer you to make, made by rare scheme — two bearing rotor during rotation intersect. To build it is not very difficult — especially as the engine are well-known modelers rubber tubing. Energy stored in them when you twist, enough to fly a small model of this type. The diameter of the rotor is 600 mm, and each of them has its own shaft, both rotating in opposite directions, which provides a synchronizing mechanism. Four gears cut from metal gears with a suitable external diameter, which you can pick up from parts of an old alarm clock or a broken clockwork toy. After processing, the thickness of each gear should be about 2 mm, the diameter of inner hole is 2 mm.
The housing in which are mounted the shafts of the rotors and the synchronizing mechanism, cut and bent sheet of aluminum with a thickness of 0.5 mm. rotor Shafts from steel wire Ø 2 mm; they can also be made of a knitting needle of suitable thickness. Mount gears to shafts — steel pins Ø 0.8 mm holes for them first serverlists in gears, but directly in the Assembly process and in the shafts of the rotors.
Bushings rotors — aluminum. The blades are cut from balsa plates 2 mm thick and fixed to the sleeve with glue. After gluing the rotors need to be balanced.